#include "TCanvas.h"
#include "TF1.h"
#include "TH1F.h"
#include "TFile.h"
#include "TTree.h"

void TestSort(){
TFile *f1=TFile::Open( "Test.root", "READ" );
TTree *T = (TTree*)f1->Get("tree_name");
 TCanvas *c1 = new TCanvas("c1","Sorting canvas",10,10,900,700);
 TH1F *spectrum = new TH1F("spectrum", "",4000,10,4010);
 c1->cd(1);
 TREE->Draw("X.GE4>>spectrum");  //Error is generated for this line
 spectrum->SetLineColor(2);
}